Method for manufacturing and packaging a pet collar

ABSTRACT

A method for the manufacture of a packaged pet collar which includes preparing a blended composition of a vinylic resin, an ectoparasiticidally effective amount of recrystallized phosmet and a plasticizer, extruding the composition into a continuous length, cutting the extruded length into individual segments, affixing a buckle, and thereafter packaging the resultant pet collar in a pouch of spunbonded olefin. The packaged collar is characterized by the absence of offensive mercaptan type odor upon opening the package.

This is a division of application Ser. No. 206,916, filed Nov. 14, 1980,now U.S. Pat. No. 4,348,321.

This invention relates to an improved pet collar which provideseffective and long-term control of ectoparasites of pets and to themethod of manufacture.

Prior to the present invention, there has not been available a petcollar which provides effective and long-term control of theectoparasites (fleas, ticks and mites) of pets. Pet collars nowavailable which provide effective control for fleas and ticks sufferfrom one or more draw-backs. The pet collars now in use provide forcontrol of fleas only or, in the case of a collar for both fleas andticks, the period of effectiveness is up to five months.

The aforementioned problems of pet collars for the control ofectoparasites are overcome by the improved pet collar of the presentinvention. In addition to providing effective and long term control ofboth fleas and ticks, the pet collar of the present invention controlsmite infestations that cause sarcoptic mange, a major problem for dogs.The pet collar of the present invention is prepared from a compositioncomprising a solid synthetic polymer such as a vinyl polymer andcopolymers thereof, recrystallized phosmet and plasticizer.

Prior art pet collars for the control of ectoparasites are described by,for example, Aries et al., U.S. Pat. No. 3,814,061 (1974), Grubb &Baxter U.S. Pat. No. 3,852,416 (1974), Greenberg U.S. Pat. No. 3,918,407(1975), Miller & Morales U.S. Pat. No. 3,944,662 (1976), Milionis &Spicer U.S. Pat. No. 4,041,151 (1977), Pasarela, U.S. Pat. No. 4,145,409(1979), Greenberg and Cloyd U.S. Pat. No. 4,158,051 (1979), Dick andRomoi U.S. Pat. No. 4,150,109 (1979) and von Bittera et al., U.S. Pat.No. 4,225,578 (1980) and Aries, French Patent Publication No. 2,267,045(1975). The Aries French Publication describes a large multitude ofpesticides which are alleged to be useful in pet collars for the controlof ectoparasites. Aries does not describe a composition for pet collarscontaining phosmet; however, in the multitude of possible ingredientswithin Aries description is included phosmet. In addition, Aries doesnot recognize the problem of offensive odor associated with a pet collarcontaining phosmet and does not suggest any solution to the problem.

The present invention provides a pet collar containing phosmet whichovercomes the offensive odor associated with phosmet and method ofmanufacture thereof.

The pet collar of the present invention is characterized by being freeof the offensive odor associated with phosmet, in addition, the petcollar of this invention is characterized by being essentially dry andhaving the property of providing a self-replenishing coating ofparticles of the active ingredient (phosmet) on the surface of thecollar by migration of the active ingredient from the body of thecollar, the migration occurring whenever particles of the activeingredient are displaced from the surface of the collar.

In preparation of the pet collar of the present invention, there can beemployed any suitable solid synthetic polymer which is satisfactorilycompatible with the plasticizer employed and recrystallized phosmet. Thepolymer needs to have adequate strength and flexibility to withstandshaping into a collar without cracking or crumbling and sufficientdurability to withstand normal wear. Further, the resin must be one fromwhich the plasticizer will not exude at normal temperatures andconditions, but, yet will permit adequate migration of the activeingredient from the body of the collar to the surface thereof. Theforegoing requirements of the resin are fulfilled by solid vinylicresins, that is, a polymer form by polymerization through a vinylicdouble bond. Vinylic resins are typified by the polvinyl halides, suchas polyvinyl chloride, polyvinyl chloride-vinyl acetate and polyvinylfluoride; the polyacrylate and polymethacrylate esters such aspolymethyl acrylate and polymethyl methacrylate; and polyvinyl benzenessuch as polystyrene and polyvinyl toluene. Preferably, the resin is ahomopolymer or copolymer of vinyl chloride. The resin comprises fromabout 40% to 70%, usually from 45% to 65%, by weight of the totalcomposition.

Plasticizers suitable for preparing the pet collar of the presentinvention are those conventionally employed in plasticizing solidvinylic polymers. The particular plasticizer or plasticizers employedwill depend upon the polymer and its compatibility therewith. Suitableplasticizers include esters of phosphoric acid such as tricresylphosphate, esters of phthalic acid such as dimethyl phthalate anddioctyl phthalate, and esters of adipic acid such as diisobutyl adipate.Other esters such as those of azelaic acid, maleic acid, rincinoleicacid, myristic acid, palmitic acid, oleic acid, sebacic acid, stearicacid and trimellitic acid as well as complex linear polyesters,polymeric plasticizers, and epoxidized soybean oils may be used. Theplasticizer comprises from about 15% to 50%, usually 20% to 45%, byweight of the total composition.

The active ingredient, recrystallized phosmet, is included in anectoparasiticidally effective amount, generally from 5% to 18%, byweight of the total composition.

Phosmet has the chemical name, 0,0-dimethyl S-phthalimidomethylphosphorodithioate or N-(mercoptomethyl)-phthalimide S-(0,0-dimethyl)phosphorodithioate and is described by Fancher, U.S. Pat. No. 2,767,194(1956). Commercial phosmet has an offensive odor. The odor ischaracterized as a mercaptan type odor. Following incorporation ofphosmet into a resin collar, the odor, nevertheless, persists. U.S. Pat.No. 2,767,194 teaches purification of phosmet by crystallization fromalcohol. Using alcohol, however, the offensive mercaptan odor is stillpresent. In accordance with the present invention, technical phosmet isessentially free of mercaptan type odor by recrystallization of thetechnical phosmet from a mixture of hydrocarbon solvent and alcohol inthe ratio of from about 1:2.5 to 1:1, respectively, by weight;preferably, from about 1:2 to 1:1. Preferably, the hydrocarbon solventis an aromatic hydrocarbon such as toluene and the alcohol is methanol.

In the preferred embodiment, the recrystallization is repeated twice asdescribed more fully in the examples. As used herein, the term"recrystallized phosmet" refers to phosmet obtained by therecrystallization of technical phosmet from a mixture of hydrocarbonsolvent and alcohol.

In the manufacture of a pet collar of the present invention, acomposition comprising vinylic resin, recrystallized phosmet andplasticizer is extruded or injection molded into the shape of a collar,buckle or similar fastening means affixed, and the collar sealed in apouch made of a packaging material of fibrous, spunbonded olefin. Asuitable fibrous spunbonded olefin is spunbonded polyethylene.Preferably, the spunbonded olefin is a high density polyethyleneproviding a packaging material having a thickness of about 5 to 10 milsand a basis weight of about 40 to 110 grams per square meter. An exampleof the preferred fibrous, spunbonded olefin packaging material is a highdensity polyethylene manufactured by E. I. DuPont De Nemours & Co.,Wilmington, Del. under the trademark Tyvek, for example, Tyvek type 10.The use of a spunbonded olefin as the packaging material results in acollar of the present invention which is free of offensive odor uponreceipt and opening of the packaged collar by the user. The use ofmaterials such as foil, saran, polyethylene coated paper and nylonlaminate conventionally used as packaging materials resulted in packagedcollars which on opening yielded an offensive mercaptan type odor.

Other ingredients such as stabilizers, lubricants, fillers, deodorants,perfumes and coloring materials can be included in the compositions forpreparing the pet collar of the present invention without changing thefundamental properties thereof. Suitable stabilizers are theantioxidants and agents which protect the resin from ultravioletradiation and undue degradation during processing such as extrusion, awide variety of which are commercially available. Some stabilizers suchas epoxidized soybean oils serve also as a secondary plasticizer.Stearates including stearic acid and low molecular weight polyethyleneare examples of lubricants which can be used. These ingredients may beused in a concentration of up to about 20% by weight of the totalcomposition.

Within a short time after processing, fine particles or crystals ofphosmet migrate from within the body of the collar and form a coating ofparticles or crystals, resembling a dust or powder, on the surface ofthe collar. As the particles of phosmet are displaced or shaken from thesurface of the collar due to the normal activity of the animal,additional particles appear by migration from the body of the collar toreplace particles displaced from the surface--i.e., the displacedparticles are replenished continuously. The normal movement of theanimal results in phosmet crystals being distributed substantially overthe entire coat of the animal and effecting its ectoparasiticidalactivity over a large part of the animal's body. Fleas and ticks arecontrolled by the collars of the present invention for up to about oneyear.

As used herein, the term "pet" means a dog or cat.

The following examples are provided to illustrate the practice of thepresent invention. Parts are by weight. Temperature is degreescentigrade unless otherwise specified.

EXAMPLE 1

To a glass lined vessel equipped with agitator and condenser is added216 parts toluene and 197 parts methanol followed by 500 parts technicalphosmet, with agitation. The mixture is heated, with continuousagitation, until the phosmet dissolves and then heated at reflux (64°)for about 30 minutes. The solution is cooled to about 0° to 5°, seededwith phosmet crystals if necessary, and then, with continuous agitation,maintained at about 0° to 5° for about one hour. The mixture is thenfiltered using a Furan filter and saving the mother liquor for reuse.The vessel is rinsed with 270 parts cold methanol (5°) and precipitatewashed with the cold methanol. The precipitate is collected and added tomixture of toluene (209 parts) and methanol (190 parts). The mixture isagitated and heated at reflux for about 30 minutes and then cooled to 0°to 5°. After about one hour, the mixture is filtered and washed asabove, air dried and then dried for about 18 hours at 20° to 30° toyield recrystallized phosmet, m.p. 70°-72°, white to slightly off-whitecrystals with no mercaptan type odor.

Technical phosmet is manufactured by the Stauffer Chemical Company.

EXAMPLE 2

A mixture of 150 ml of toluene, 150 ml. of methanol and 300 g. oftechnical phosmet is heated in a hot-water bath until homogenous. Thesolution is poured into Buchner funnel with suction flask. The flask isagitated vigorously in ice water bath until all crystals formed. Liquidis poured off and filtered through Buchner funnel with suction, rinsingwith cold methanol (20 ml). The crystals are dried at 55° for one hour.Color of technical phosmet (pinkish) changed to white to slightlyoff-white and only very faint mercaptan type odor remained. Theforegoing procedure is repeated and the crystals, air dried, had nodetectable mercaptan type odor. Purity 98% and mositure less than 2%water.

The use of methanol alone as the solvent improved the color but did notremove the mercaptan type odor. The use of toluene and methanol in theratio of 1:3, respectively, in the above procedure, changed the color oftechnical phosmet to off-white but, the mercaptan type odor remained.

The above procedure was repeated using 1.0 kg. of technical phosmet, 0.5liter of toluene and 1.0 liter of methanol yielding recrystallizedphosmet, white to slightly off-white, having no mercaptan type odor.

EXAMPLE 3

Polyvinyl chloride (49.4 parts) is mixed in a high intensity mixer(Henschel) at 3600 rpm until the polymer reaches about 140° F. To thepolymer is added epoxidized oil (2.3 parts), bis(2-ethylhexyl)terephthalate (29.5 parts) and stabilizer (0.8 parts) with mixing,135°-155° F. Recrystallized phosmet (17.3 parts) is added and mixeduntil a homogenous dry blend is obtained. To the blend, with mixing, isadded titanium dioxide pigment (0.5 part) followed by stearic acid (0.2part). The blend is then cooled to about 90° F.

The polyvinyl chloride is a high molecular weight polyvinyl chloridehomopolymer under the name Diamond 550 by the Diamond ShamrockCorporation.

Epoxidized oil is 2-ethylhexyl epoxytallate known as Drapex 4.4 from theArgus Chemical Company.

Stabilizer is Mark 1500, phosphite stabilizer, of Argus ChemicalCompany.

Titanium dioxide is white pigment known as PMS 355-T by Plastic MoldersSupply, Ft. Worth, Tex.

EXAMPLE 4

The blend prepared in Example 3, is extruded using a single stage screwwith a screw temperature of 320° F., die temperature of 330° F. andbackpressure of about 300 psi. The extrudate, 0.563 inches wide and0.130 inches thick, is cooled by running through a water bath and thendried using a compressed air drier tube. The extrudate is then cut intosegments of 22 inches, a buckle added by a steel rivet and the resultingcollar rolled or coiled. The rolled collar is then packaged in a pouchmade by placing the rolled collar between two sheets of spunbondedolefin measuring 4.5 by 5.5 inches each and sealing the four sides. Thesealing of the spunbonded olefin to form the pouch is accomplished usingimpulse sealing to seal the material to itself or using thermoplasticresin adhesive. The pouch is free from punctures and slits and iscompletely sealed. The spunbonded olefin used in the foregoing is a highdensity polyethylene under the name Tyvek 1073D by E. I. DuPont DeNemours & Co. (Inc.).

Pet collars of the present invention manufactured by the foregoingmethod do not have the offensive mercaptan type odor when manufacturedor after storage, including storage in the sealed spunbonded olefinpouches, of several months at room temperature. In comparison, collarsof the present invention when made as above with the exception ofsealing in a pouch made of conventional packaging material such aspaper/foil laminate emit an offensive mercaptan type odor upon openingthe pouch after storage for only one month at room temperature or below(50° F.).

Collars made in accordance with Examples 3 and 4 were fitted on dogs fortesting against the American Dog Tick (Dermacentor varabilis), Brown DogTick (Rhipicaphalus sanguineus), and fleas (Centocephalus sp.). Thecollars were found to provide effective control of both ticks and fleasafter ten months. The collars were not irritating to the dogs throughoutthe test.

What is claimed is:
 1. A method for the manufacture of a packaged,flexible, solid, ectoparasiticidally effective pet collar whichcomprises the steps of:(a) preparing a thorough blend of a solidcomposition comprising a solid, vinylic resin, ectoparasiticidallyeffective amount of recrystallized phosmet and plasticizer; saidrecrystallized phosmet having been prepared by recrystallization ofphosmet in a toluene and methanol mixture in which the ratio of tolueneand methanol is within 1:2.5 to 1:1 by weight, and being free ofoffensive mercaptan type odor; (b) extruding said composition to form acontinuous length of extrudate having a width and thickness suitable fora pet collar; (c) cutting said extrudate into individual segmentssuitable for a pet collar and affixing a buckle at one end of thesegment; and (d) sealing each segment in a pouch made of spunbondedolefin, said packaged collar characterized by the absence of offensivemercaptan type odor upon opening of the package.
 2. The method accordingto claim 1 wherein the resin is a homopolymer or copolymer of vinylchloride and the spunbonded olefin is high density polyethylene.
 3. Themethod according to claim 2 wherein the resin is polyvinyl chloride. 4.The method according to claim 2 wherein the spunbonded olefin has athickness of about 5 to 10 mils and a weight of about 40 to 110 gramsper square meter.